In relation to being a sequel to The Wall, the album is Pink's reflection of how he has devastated those around him as well as his own life. He realizes that he is useless to society and cannot communicate. His reflections on the past are mostly dark, minus the one where he perhaps thinks there is still a chance between him and his wife. Overall, however, the album is supposed to reflect the feeling of emptiness he has from a lack of communication throughout his life and how attempts to make it better are more or less futile.
Sorry for being so dark. This is just how I interpreted the album. Anyways, if you liked that, be sure to check out my other works. :D